Processes for film or sheet production by inflation extrusion molding have hitherto been used extensively because films or sheets can be efficiently produced by the processes. However, in the case where a pressure-sensitive adhesive sheet or tape or the like which has a pressure-sensitive adhesive layer on one side is produced by inflation extrusion molding, the following trouble arises. When a pressure-sensitive adhesive sheet which has been extruded from an extruder and inflated into a cylindrical shape is transferred, while being flattened, with stabilizers constituted by guide rollers arranged in rows, then the pressure-sensitive adhesive layer on one side of the pressure-sensitive adhesive sheet sticks to the guide rollers and, hence, the length over which the sheet being transferred is in contact with the guide rollers fluctuates. Because of this, the pressure-sensitive adhesive sheet moves intermittently between the stabilizers and this may result in surface waviness or wrinkles of the pressure-sensitive adhesive sheet.
There is hence a technique in which the surfaces of the guide rollers constituting stabilizers are coated with Teflon to diminish the sticking of pressure-sensitive adhesive layers (see, for example, patent document 1).
Patent Document 1: JP 50-020578 B
However, in the case where a long guide roller is used as each of the guide rollers constituting the stabilizers, the direction of rotation of the guide rollers do not coincide with the direction of resin material spreading when the resin material which has been inflated into a cylindrical shape by blown-film extrusion is folded so as to have an elliptic section. Because of this, even when the surfaces of the guide rollers have been coated with Teflon or the like, the resin material shakes undesirably and is not smoothly spread into a flat tube shape having an elliptic section, resulting in the occasional occurrence of folding wrinkles.
Especially in the case of sheets or films having a pressure-sensitive adhesive layer formed on one side, such as pressure-sensitive adhesive sheets, it has become difficult to cope with the recent pressure-sensitive adhesive layers of various kinds with the mere coating of the surfaces of the guide rollers constituting stabilizers with Teflon or the like as shown in patent document 1. Namely, the mere coating of the surfaces of the guide rollers constituting stabilizers with Teflon or the like as shown in patent document 1 is ineffective in preventing sticking to the guide rollers when the pressure-sensitive adhesive layer formed has high pressure-sensitive adhesive properties, and it is difficult with this technique to fold the cylindrical inflated pressure-sensitive adhesive sheet into a flat tube shape having an elongated elliptic section with avoiding the occurrence of wrinkles or the like on the sheet surface.